i think there is some legitimate worry about functionality. a better alternative would be to return more of the government's power and functionality to the states. then direct representation on the national level is not as important.
friscodawg makes a good point. have the senators appointed by the states by whatever process the state legislature chooses.
then eliminate federal income tax. tax each state proportional to the number of representatives in the house, and let each state decide how to collect revenue.
eliminate federal programs that aren't a federal job by necessity. let state and local governments do the important work so that agencies are directly accountable to the people they "serve".